English: A Crucial Delay-Early afternoon looking west across Burnside Bridge. With only a small force, but holding higher ground, Lee's men were able to defend this crucial Antietam Crossing for nearly three hours. Union General Ambrose Burnside's men launched a series of attacks to break the bottleneck at the bridge. About 1 p.m., the Confederates, outflanked, outnumbered and running low on ammunition, began to retreat. The Yankees stormed the bridge, finally crossing Antietam Creek. This painting shows Union Reinforcements crossing the bridge in preparation for the final advance. However, the time taken to cross and resupply the troops provided Lee with the opportunity to bring his final reserved on the field and turn back Burnside's attack, thus ending the bloody day.